Battery.



. F. unGEss.

BATTERY.

APPLICATION mio Dsc. 1o, |913.

yatented Nov. 30,1191

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(zar/e5 FHq/yz .5.5 I By j A UNITED STATES PATENT OFFICE.

CHARLES-F. BURGESS, 0F MADISON, WISCONSIN, ASSIGNOR T0 C. BURG-ESS LABORATORIES, A CORPORATION OF WISCONSIN.

BATTERY.

` Application filed December 10, 1913.

T o ZZ whom t may concern f Be it known that I, CHARLnsF. BURGEss, a citizen of the United States, residing .at Madison, county of Dane, State of Wisconsin, have invented certain new and useful' The present invention relates to dry batteries of the Le Clanche type, wherein one electrode is of zinc and the other' is of carbonaceous material, and the electrolyte consists of a solution of ammoniui chlorid with zinc chlorid added as desired, and wherein a Solid depolarizing material is present at one electrode to oXidizethe hydrogen there set free.

It is the object ofthe present invention to increase the efficiency and capacity of such batteries by improvements in their mechanical construction and `in the arrangementV of parts, but more particularly to improve them in such a way as to obtain larger current output, quicker recovery, better internal conductivity, and greater reliability. As contributing to these ends, and as an important factor in obtaining the results desired, I make use of a new depolarizing mixture containing carbonaceous material and a manganese depolarizer, the carbonaceous material being in graphitic form and in an extremely fine state of subdivision, and the manganese depolarizer being 'of such character as to coperate to good `advantage y with this graphite.

In the accompanying drawing, forming part of this specification, there is illustrated in enlarged cross-section a battery or cell built in accordance with my present invention. This particular cell is of the miniature type suited for use with portable hand lamps, but my invention can be used in batteries of larger size, such as those ycommonly used for telephone and ignition work.

In the drawing, the celllcomprises a zinc container 1 lof usual construction within which'is a carbon rod 2 with a brass terminal cap 3, this rod being` closely enveloped by a tightly compressed block 4 of depolarizing mixture. Enveloping the block Specification of Letters Patent.

PatentedNov. 30, 1915.

serial no'. 805,675. i

4 of depolarizing mixture may be and preferably is an envelop 5 of bibulous material, such as cloth gauze, whichmay be slipped over the block 4 after the latter has been tightly compressed about its carbon rod 2. A winding 6 of thread or string may hold the envelop in the form of a bag gathered togethe?y and tied tightly about the carbon ro at To prevent local action the close proX- I imity of the depolarizing mixture with the bottom of the zinc container, compared with its proximity to the side wall, the lower part of the gauze envelop is impregnated with paraffin at 8.. Furthermore, in 4using the exceedingly fine graphite here contemplated, there is danger, except for the paratlin, that the graphite, by migration orl otherwise, will pass over to the zinc surfacev4 and so cause rapid shelf deterioration. The finer the' graphite the greater is the liability to trouble from this cause-unless special precautions are taken.

To assemble the cell, the carbon rod 2 with its compressed blocke` and gauze envelop is introduced into the zinc container until it rests on the vbottom thereof, and a paste 9 is poured in to lill the annular Space between the envelop and .the zinc container. Preferably a starch water paste is used, containing ammonium chlorid and zinc chlorid in such propo-rtions that upon standing for a few minutes the paste gelatinizes and becomes semisolid. y

The starch paste is poured in until it completely covers the top of block 4, and above the top of the starch paste, with an air gap lO intervening, is introduced a paraffin washer 11 above which the cell is filled up with a p itch seal12 substantially to the top .of the zinc container, and 'with brass cap 3 projecting upwardly through the pitch, so

that contact may be established with the external circuit.

The` depolarizing mixture whereon the tery of my invention, and although .the characteristics of the material which is used are somewhat difficult of definition, and the reasons for theadvantageous results are in some 5 yrespects obscure, nevertheless the disclosures hereinafter made will enable those skilled in the art to construct batteries far superior to those heretofore commonly made; not only in the current output obtainable, but also in recovering power and ability to resist deterioration while in storage. F or instance, batteries forign'ition use, known to the trade as No. 6 batteries, and having dimensions approximately six inches high and two and one-half inches in diameter, when connected to a four ohm-resistance will drop to 0.75 volt in l() hours of continuous discharge; whereas batteries of the same dimensions and built in accordance with my present invention will operate continuously on the same resista-nce for 150 hours before dropping to 0.75 volt.

The carbonaceous material used by me is graphitic in character, and for a complete understanding of its characteristics and its relation to various kinds of graphite heretofore used, it is desirable to'set forth herein some of the distinguishing characteristics of various kinds of graphite.

In the following table appear data on ten kinds of graphite together with an enumeration of their respective characteristics. These various materials were obtained from the International Acheson Graphite Company of Niagara Falls, and are designated by their trade numbers:

Electri- Relative Relative tgdgo Fineness. Pes'nt' calresistvolume -volume ance. dry. in water. 40

92 7. 20 160 935 3. 2 83 2. 61 G87 93 3. 2 96 4. 46 160 1. 04, 3. 4 99. 5 77 115 1. 38 4. 6 99. 5 00 128 1. 34 5. 3 69 88 3. 50 135 915 2. 5 99. 5 22 10() 1. 41 5. 3 575 99 52 140 1. 21 5. 6 A-3 Impalnahle 9. 55 568 2. 18 14. 5 75o t I 6. 3o .434 2. 2s 14. s

` tween twoelectrodes, the values given in the above table were determined and are eX pressed in ohms `per lineal linch of column one inchin diameter. I

The relative volume dry is determined by 05 placing ten grams of graphite in a cylinder one inch in diameter and tapping the container until the material settles to a constant volume. The figures in the above table indicate the height in inches occupied by the ten grams of graphite.

The relative volume in water as given in the above table is determined by placing one gram of graphite in a 25 cubic centimeter graduated glass cylinder having an internal diameter about 11/16, adding water so that 75 the total volume is 25 cubic centimeters and allowing the graphite to settle for one hour. The apparent volume of the settled graphite is then measured on the graduated scale and the figures in the above table indicate in 3o cubic centimeters the volume occupied by one gram of graphite after settling .for one hour in 25 cubic centimeters of water.

0f the several grades of graphite appearing in the table the first seven are listed by the International Acheson Graphite Company as being battery grades, and the first two are the grades which have been in most general use in this country for the manufacture of standard size of dry batteries. The last two grades are the kind used by me in accordance with this invention. By reference to the table it will be seen that these two grades used by me have certain distinctive properties, being distinctly liner than all the othersin fact so fine that they cannot be designated except by the term impalpable. That is the term under which they are sold 'by the International Acheson Graphite Company, and in the claims of this speclication where the term impalpable is used Ihave reference to materials much finer than even tho-se grades of Acheson graphite which are graded by passing through a 200 mesh sieve. l This impalpable grade may be further distinguished by ,its light luify character, which gives it great bulk as compared with some of the coarser grades and which gives to it an apparently low specific gravity.

The great diil'erence in the ineness of the imf 110 palpable graphite and that of the 200 mesh graphite heretofore used can be readily detected b means of a high power microscope. Itis di cult, if not imposslble, to give the exact dimensions of the particles; but it is my present belief that they are of less than 1/2000th of an inch in' diameter. The difference lcan better be detected by the method of settling out of water in the manner indicated for determining the figures in the last column of the above table. From this it is seen that the volume occupied by the impalpable powder is from three to live times that occupied by the commonly used grades.

. By reference to the above table it will be seen that the electrical resistance of the l graphite used by me is approximately four` times'that of graphites as heretofore used.

It is not lcertain that this is a characteristic of the graphite itself but may be due to its extreme fineness and to the greater number of contacts presented to the flow of current when the resistance measurement is made with the graphite dried'and under pressure. High resistance has heretofore been generally acepted as indicating inferiority in graphite for battery use, but with my materialsl I have found that inyspite of this apparent inferiority as regards resistance the impalpable graphite possesses striking advantageous characteristics which I have discovered and which make it possible to impart the exceptional qualities to dry cells by its use.

As to depolarizing mz terial for use with the graphite a considerable variety of materia-ls is available, fir the peculiar characteristics of the graphite used by me are such that any one of several grades of depolarizing compounds can be used with satisfaction. I may use pyrolusite or natural manganese dioxid or vI may use artificial or recovered manganese from any one of severaldifferent sources as claimed more particularly in my co-pending ap lication, Se-

' rial No. 862,284, iledSeptem er 18, 1914, as a division hereof. Artificial manganese is obtainable as a by-product from several different industrial processes, such as the -manufacture of chlorin, and bleaching powder, and saccharin, and-in this country has been marketed for rmany years 4under the name recovered manganese by chemical houses including Harshaw, Fuller & .Goodwin Company of Cleveland, Ohio, John S. Lamson & Bro., of New York and The Roessler & Hasslacher Chemical Company,

of New York.

In using any one of the several kinds or grades of manganese depolarizer it is4 advisable to recognize its particular individual y of a lower specific gravity. A suitable mix'- ture maybe made in the proportions of 100 grams impalpable graphite, 21` grams pyrolusite, 13 grams ammonium chlorid, and 15 grams water. Y

The pyrolusite vas suppliedon the market is much coarser than are the various grades of recovered manganese. A common degreeof fneness of pyrolusite is that defined as ma terial which passes through a mesh screen Recovered manganese, being formed by a. chemical precipitation process, consisting oit much more minute particles than thoseI Which just pass through such a screen, and

the relative degree of fneness has much to do with the relative proportions of impalpable graphite which must be added to produce the best results.

As to degree of hydration, this is less in pyrolusite than in artificial or recovered manganese in generahand sincewith'the use of pyrolusite it is only the hydrated materia-l which participates in the depolarizing action (though some of the un hydrated may become hydrated by secondary action, and later become available for delivering oxygen to combine with the hydrogen resulting from the flow of current) the proportion of pyrolusite, weight for weight, should be greater than When the more highly hydrated depolarizers are used. 'F or instance, using a standard gradel of recovered manganese, a suitable mixture is aa follows: 12 grams impalpable graphite, 36| grams recovered manganese, 3.5 grams ammonium chlorid, 3.3 grams zinc chlorid, 12 lgrams water.

Throughout the scientific literature ,relating to Le Clanche cells the term manganese is freely used to designate pyrolus'ite, which is manganese dioxid MnO, partially hydrated.l In elementary text books the chemistry of depolarization is' commonly said to result from "the chemical union of the electrolytic hydrogen with-oxygen given up by the manganese dioxid, but for several years it has been recognized by electro-chemists that the reaction is more complexl than this and involvesthe union of hydrogen with the OH radical of the pyrolusite or other manganese depolarizer, necessitating therefore the presence of manganese oxid in a hydrated form, suchas is vpresent in pyrolusite, (and even in the ore before Washing and grinding), and such as is present inthe various kinds of recovered manganese now obtainable on the market.

v`Without desiring to be limited by anyparticular theory for the cause of the beneficial effects which I have 'been able to produce -as above described, one explanation may be presented as follows: In spite of the apparent high resistance of the'impalpable graphite, it gives excellent character- "istics to the mix which goes .into the dry cell construction, 'partly by flowing readily into interstices between the manganese parti- `cles,thereby forming a more homogeneous and continuous path for the flow of current to the carbon rod,/t han would be the case were graphite in larger particles `ernployed, and partly by the increased effec- .tivene'ss of ythe depolarizer when the materials are in thismost intimate contact.

iis

The conductivity of graphite, even the relation of 10,000 and over to one) that the 13 graphite must be relied upon entirely as the conducting medium for, the flow of current through thel mixture Which surrounds the carbon rod of the battery. The electrical vresistance of pyrolusite measured according to the method above outlined for resistance measurements of graphite is from 3,500 to 10,000 ohms per lineal inch, or a conductivity less than 1/10,000 of thatof graphite. Recovered manganese in its more common forms has even less conductivity, and by the above designated mode of resistance measurement a typical material which has been extensively employed by me has a resistance of 136,000 ohms per lineal inch, or a yconductivity less than 1/270,000y that of the impalpable graphite and less than 1/2-0th that of pyrolusite.

The effectiveness of depolarizing material isdependent upon the intimacy of its contact with the conductive graphite,l and this intimacy of contact is greaterl Where the impalpable graphite is use-d than Where the coarser grade isemployed. The capacity of a dry cell for delivering current is determined, in a measure, by the amount of Water which the depolarizing mixture will hold. This amount of Water is greaterwith the use of the impalpable graphite than with the use of thefcoarser grades, as is evidenced by the greater absorptlon of Water Whichv the impalpable "material possesses.

The above disclosure sets forth all of the data necessary to enable those skilled in the a'rt to'practise my invention, irrespective of the origin of the manganese depolarizer, and

whether pyrolusite is used or the more finely divided recovered manganese. It has been yfound 1n practice that the recovered manganese varies somewhat in purity depending upon 1 ts origin, and 1t 1s goed practice in preparlng it for the battery to WashV it with water and so take out any soluble impuri-y ties that may be present, after which the resldue mav be dried and putqinto such physical condition that it may be readily mix'ed with the otherl ingredients.

In the commercial manufacture :of bati. 4teries accordlng to. my process, the impalpable graphite has been obtained from the International Acheson Graphite Company,

it being a secondary product resulting from their methods of air separation.

Iclaim:

1. A dry battery, having a depolarizing' -mixture consisting of impalpable graphite with a manganese'depolarizer andsuitable salts and Water.

-conductivity -not greater material of which at least 30 per cent. is in the form of an impalpable powder.

8. A depolarizing mixture for batteries consisting essentially of impalpable graph-4 ite, a manganese depolarizer in part hydrated, and usual saltsand Water.

4. A depolarizing mixture for dry batteries consisting of carbonaceous material, a manganese depolarizer and usual salts and -water, sa1d carbonaceous material being in the graphltic form and 1n a physlcal condi- 6. A mixure for dry batteries containing .Carbonaceous material substantially all of which is`in impalpable form and hydrated manganese depolarizer having when dry a thanthat of pyrolusite, substantially as described.

7. A depolarizingmixture for dry batteries, consisting essentially of impalpable graphite and pyrolus1te.

8. A depolarizing mixture for a battery comprising impalpable graphite and manganese dioxid. n

.9. In a dry battery, afdepolarlzing mixture consisting of impalpable graph1te with recovered manganese andsuitable salts and Water. y

10. In a dry battery, a depolarizing mixture containing carbonaceous material of which at least 30% is in impalpable form, together with recovered manganese.

1l. A depolarizing mixture for batteries,

consisting of impalpable graphite and a hydrated manganese depolarizer having a com.4

ductivity when dry less than that of pyrolusite.

.12. In a dry battery, a depolarizlng mixture consisting of impalpable graphlte with recovered manganese and suitable salts and Water, said recovered rmanganese belng, of

the variety obtained as a by-product in the manufacture of saccharin.

In testimony whereof I affix my signature,

in presence of two'witnesses.

CHARLES EBURGESS.

' Witnessesz` L. S. LUNDER, J. E. BYRNs. 

